236 The Identification of Species 



present certain definite morphologic, biologic, cultural, and perhaps 

 pathogenic characters which establish the types independently of 

 minor variations. 



"The most marked of these types we select to become the centers 

 of groups, around which are gathered all related species or varieties." 

 " The division of the bacteria into groups, so far as grouping was pos- 

 sible, is outlined in the following tables:" 



A PROPOSED SYNOPSIS OF GROUPS OF BACTERIA 



Bacterium 



I. Without endospores. 



A. Aerobic and facultative anaerobic. 



a. Gelatin not liquefied. 



* Decolorized by Gram's method. 



t Obligate aerobic. Acetic Ferment Group. 

 tf Aerobic and facultative anaerobic. 

 Gas generated in glucose bouillon. 



Gas generated in lactose bouillon. Bact. Aerogenes 



Group. 

 Little or no gas generated in lactose bouillon. Fried- 

 lander Group. 

 No gas generated in glucose bouillon. 

 Milk coagulated. Fowl Cholera Group. 

 Milk not coagulated. Swine Plague Group. 

 ** Stained by Gram's method. 



t Gas generated in glucose bouillon. Lactic Ferment Group. 



b. Gelatin liquefied. 



* Colonies on gelatin ameboid or proteus-like. Bact. radiatum 



Group. 

 ** Colonies on gelatin round, not ameboid. Bact. ambiguum Group. 



II. Produce endospores. 



1. No growth at room temperature, or below 2 2°-2s°C. Thermophilic 



Group. 



2. Grow at room temperatures. 



a. Gelatin liquefied. Anthrax Group. 



b. Gelatin not liquefied. Bact. p^calis Group. 



Bacillus 

 I. Without endospores. 



A. Aerobic and facultative anaerobic. 



a. Gelatin colonies roundish, not distinctly ameboid. 



* Gelatin not liquefied. 



t Decolorized by Gram's method. 

 Gas generated in glucose bouillon. 

 Milk coagulated. Colon Group. 

 Milk not coagulated. Hog Cholera Group. 

 No gas generated in glucose bouillon. Typhoid Group. 

 ft Stained by Gram's method. B. muripestifer Group. 

 "■* Gelatin liquefied. 



t Gas generated in glucose bouillon. B. cloac/E Group.. 

 tfNo gas generated in glucose bouillon. Include a large number 

 of bacteria not sufficiently described to arrange in groups. 



b. Gelatin colonies ameboid, cochleate, or otherwise irregular. 



* Gelatin liquefied. Proteus vulgaris Group. 

 ** Gelatin not liquefied. B. zopfi Group. 

 II. Produce endospores. 



A . Aerobic and facultative anaerobic. 

 I. Rods not swollen at sporulation. 



a. Gelatin liquefied. ' - • 



